Solid phase extraction (SPE) is a chromatographic technique that is widely used, e.g., for preconcentration and cleanup of analytical samples, for purification of various chemicals, and for removal of toxic or valuable substances from aqueous solutions. SPE is usually performed using a column or cartridge containing an appropriate material or sorbent. SPE procedures have been developed using sorbents that can interact with analytes by hydrophobic, ion-exchange, chelation, sorption, and other mechanisms, to bind and remove the analytes from fluids.
Because different SPE applications can require different sorbents, there is a need for sorbents with novel properties that have unique selectivities. These include superior wetting characteristics, selective capture of analytes of interest, and non-retention of interfering analytes. Sorbents comprising porous particles having the aforementioned properties are described in WO 99/64480 and in U.S. Pat. No. 6,322,695B 1.
The most common materials currently used are a co-polymer of divinylbenzene and N-vinylpyrrolidinone with an average pore diameter of 73-89 Å. The pore size of this material is however too restrictive for samples of biological materials.
There remains a need for SPE materials with larger average pore diameters which maintain nitrogen content in the materials as well as particle morphology.